Exponential Software Engineer interview questions

data structure, programming

First three rounds seemed ok on part of a java developer. The level was as should be anywhere in a good company. But the fourth round seemed like they wanted to kick me out, totally out of focus. The interviewer was pretending to have a lot of knowledge, and seemed to raise invalid questions like if you have a proprietary framework why do you use that, use open source ? And in the end of interview when I asked him what open source you use, the answer was we don't have our own frameworks and also we don't use open source (just code mindlessly), so in my view and also my other friends from IITs. This company is a fraud and are just creating propaganda when they actually don't seem to hire anybody/